I never got a reply from anyone on this. I finally drained the tank and dried it out, and then took some waterproof bathroom caulk and applied some carefully around the large tube leading from the tank into the top of the bowl. This seemed to do the trick in the master bath.

Adjusting the level so it doesn't run *should* be a simple matter of turning the screw on top of the ballcock assembly, so the float triggers the valve earlier. Turning the screw clockwise should cause the valve to shut off earlier and lower the water level. It is common for this to not work well as the valve wears out with age; sometimes I find I have to get in there and bend the float arm downward a little bit at a time as well.

In our second bathroom, thinking that the ballcock was worn out, I replaced it entirely. However, even on the brand new assembly, the adjustment doesn't work. I suppose it is possible that it was leaking around the large tube like the first one, and that sealing it would help. However . . .

I finally got fed up with the whole thing. Even when they're not leaking, these Rialto's won't flush worth beans. Large loads often require *two* flushes, taking *seven* gallons of water to do the job.

So we bought two Toto Drake toilets, and I've installed one in the second bathroom; the second one will be installed in the near future. The Toto Drake works better on 1.6 gallons than the Rialto ever did with 3.5. And the ballcock never requires adjustment because it doesn't use the old-fashioned float. Definitely a case in which more advanced technology works better than the brute force method of using a lot of water. I'm expecting to save money on water bills year round.

As for the small black float, I'm mainly guessing at it's purpose. However, I watched it quite carefully during a number of flushes, and it seemed to me that during a flush cycle, this little valve redirects water coming into the tank (from the water supply source) into the large tube, and thus into the bowl. My guess is that this causes water to come down around the rim, rinsing the rim, and supplying additional water for the flush. When the level in the tank drops, the valve then switches over to route incoming water into the tank for the refill process.

One of my pet peeves about the ballcock assemblies for the Rialto, besides the fact that I can't find Kohler brand parts locally, is that the third party product I *was* able to find don't have the small black float! What's worse, moving the float to the new ballcock doesn't work very well. I can pull the small float assembly out of the main body of the original (Kohler) ballcock, but the hole in the new assembly is too large!

To fix this, I went to Home Depot, bought a small length of flexible plastic tubing that fit tightly over the pipe attached to the small float, cut it off even with the end of the plastic pipe, and then used a belt sander (secured to a workbench) to carefully grind the tubing down so that it fit snugly in the hole in the ballcock. This worked very well, but what a pain in the neck! Why don't they sell the correct parts for this piece of junk.

Anyway, I'll soon have two 17 year old Kohler Rialtos for sale. Know anyone who wants them?

Good luck!

: Our house, built in 1986, has two Kohler Rialto toilets. The mechanism in this thing has something I've never seen in any other toilet. Attached to the ballcock assembly is a second little float valve which is attached to a rubber tube that runs (I think) into the rim of the bowl.

: From what I've been able to determine, during a flush cycle, this little valve redirects water coming into the tank into the tube, and thus into the bowl. When the level in the tank drops, the valve then switches over to route incoming water into the tank for the refill process.

: My problem is that water is leaking slowly into the rim. I don't think it is leaking around the flapper -- the flapper appears to provide water to the bottom of the bowl, while the tube provides water to the rim. Am I right about this? Replacing the flapper hasn't worked, though I haven't tried putting in a new flapper seat. If the leak to the rim is somehow coming from the tube, I can't tell whether it is leaking through the tube somehow, or around the tube where it feeds through the hole in the porcelain.

: Can you explain why the Rialto has this unusual setup, and how I might go about troubleshooting it and ultimately, fixing it? I have been unable to find resources that talk about this non-standard setup.